In this application, the invention is a novel heuristic mechanism of working path and backup path reservation for highly utilizable WDM mesh networks, which we call dynamic-network adapted cost selection (DAC-selection) mechanism. One of its characteristics is simple traffic distribution mechanism, and the performance of DAC-selection mechanism is superior to that of Random selection (R-selection) and Advanced Combined Min-cost selection (ACM-selection) mechanism. DAC-selection mechanism provides simple cost function by assigning proper weights to each component of the cost function and the total cost is obtained by just summing up the individual cost. Therefore, it is possible to select a best pair of working path and backup path which consumes least wavelength for reservation.